Machine and method for coating bulbs



Aug 30, 1955 J. H. GREEN ET AL MACHINE AND METHOD FOR OOATING BULBSFIR/NG /N Filed Jan. 26, 1952 T 9. NEE DN H 4 Mm -Hm HOI I -Y n y. 5 wmAug 30, 1955 .1. H. GREEN ET AL 2,716,620

MACHINE AND METHOD FOR COATING BULBS Filed Jan. 26, 1952 2 Sheets-Sheet2 ffx m /4 5 i592 INVENTORS JT H. @Jee-5N .5", /9 L OPENS/f7 ATTORNEY2,716,620 Patented Aug. 30, 1955 ffice MACHINE AND METHD FOR CGATINGBULBS James H. Green, Verona, and Stanley A. Lopenski,

Pompton Plains, N. J., assignors to Westinghouse Electric Corporation,East Pittsburgh, Pa., a corporation of Pennsylvania Application January26, 1952, Serial No. 268,412 10 Claims. (Cl. 117-94) This inventionrelates to the application of enamel to incandescent electric lamp bulbsand particularly those of the Christmas tree type.

The principal object of our invention, generally considered, is toeiiciently coat bulbs with enamel, remove the surplus therefrom, bakethe enamel thereon, and cool in an expeditious manner.

Another object of our invention is the provision of a machine forautomatically coating lamp bulbs with enamel, and particularly such ofthe ceramic type, comprising a conveyor, means for driving the same andcausing it to index from station to station, tubular means on saidconveyor for holding a series of bulbs with their axes vertical, meansdisposed at one station along said conveyor for spraying or in otherWays applying enamel on said bulbs, one by one, as they index thereat,means at a succeeding station for removing surplus enamel from thebottom edge portions of said bulbs, means at succeeding stations fordrying the bulbs and baking the enamel thereon, means for then liftingsaid bulbs olf said tubular supporting means and rotating them whilecooling, and means at the nal stations for speeding-up the cooling ofsaid bulbs prior to removal from the machine.

A further object of our invention is the method of coating incandescentelectric lamp bulbs with enamel, particularly such of the ceramic type,comprising moving said bulbs step by step while supported interiorly onhollow members, spraying enamel vertically downward on said bulbs whileso supported, forcing cleansing iluid through said hollow members toremove surplus enamel from the bottom edge portions of said bulbs,blowing air through said hollow members to remove surplus cleansingfluid, heating said bulbs to dry and bake the enamel thereon and to drythe residual cleansing fluid in bulb interiors, thereafter raising saidbulbs from engagement with the upper ends of said supporting tubularmembers while rotating the same, and finally blowing air on said bulbsto speed up the cooling thereof.

Other objects and advantages of the invention will become apparent asthe description proceeds.

In the drawing:

Figure l is a plan of a machine embodying our invention.

Figure 2 is a vertical sectional view on the line II-II of Figure l, inthe direction of the arrows, illustrating the application of enamel to abulb.

Figure 3 is a horizontal sectional view on the line III-III of .Figure2, in the direction of the arrows.

Figure 4 is a view corresponding to Figure 2, but showing a coated bulbat a subsequent position Where surplus enamel or paint is being removedfrom the lower edge thereof by streams of cleansing uid introducedthrough a hollow support.

Figure 5 is a sectional view of such a bulb in the lehr on the line V-Vof Figure l, in the direction of the arrows.

Figure 6 is a sectional view of a bulb on the line VI-VI of Figure 7,after the coating has been baked thereon,

during the process of cooling after raising it from a supporting tubularmember while causing rotation thereof due to a supporting shelfcontacting its lower edge.

Figure 7 is a plan as viewed on the line VII-VII of Figure 8, in thedirection of the arrows.

Figure 8 is an elevational View, on the line VIII-VIII of Figure 7, inthe direction of the arrows.

The purpose of the invention is to apply a smooth uniform, desirablyceramic, enamel or paint coating of predetermined color to bulbs forincandescent electric lamps, particularly those of the miniature orChristmas tree type. A machine has been produced of optimum simplicity,which can be constructed at low cost and will operate with lowmaintenance. One problem was to ascertain if a typical lime glass fritenamel could be used to coat lead-glass bulbs. It was feared that limeglass frit enamel would melt too close to the bulb softeningtemperature, thereby resulting in bulb deformation on enamel baking. .Itwas found, however, that lead glass bulbs could be used with presentlime frit enamels, as well as lead frit enamels, with a satisfactorybaking and without bulb deformation.

The elements of the machine to be described in detail are anindexing-type horizontal conveyor driven by suitable means, a simplenon-rotating bulb holder, a continuous down-flush recirculating coatingsystem, an end cleaning method which employs an internal water spray forremoving surplus paint from the lower edge portions of Said bulbs toavoid interfering with butt-sealing thereof, a simple refractory burnerdesigned so as to form a furnace or lehr, and a pre-heat section whichobtains its heat for drying by using electric strip heaters and theproducts of combustion from the burner.

Referring to the drawing in detail, like parts being designated by likereference characters, the apparatus of our invention, one embodimentonly of which is illustrated, comprises a conveyor for supporting andtransporting a series of bulbs, such as those used in the manufacture ofincandescent lamps, such bulbs being designated by the referencecharacter 11. These bulbs are supported during processing on a series ofhollow or tubular members 12, in turn carried by a conveyor, generallydesignated 13, and indexed from station to station.

Lamp conveyor and frame The frame of the present embodiment comprises atable 14 which extends the length of the machine and may be in the formof a channel member with the web at the top and the flanges projectingdownwardly. This table may be supported from the door by a plurality oflegs (not shown). Upstanding from the table are a pair of bearings 15and 16 which carry the drive shaft 17.

The conveyor for the lamps 11 comprises a series of links 18 forming achain 19 and to which a series of lampsupport members 21 are connected,as by means of screws 22. The chain passes around sprocket wheels 23 and24, only diagrammatically illustrated in Figure 1, on shafts 25 and 26,respectively.

Drive mechanism The power drive mechanism for the conveyor comprises amotor or other prime mover 27 driving, through reduction gearing 28, achain 29 passing over sprocket Wheel 31. The latter is mounted on driveshaft 17 turning in the bearings 15 and 16 on the table 14. The shaftcarries at one end a cam 32 in which rides a roller 33, on a lever 34pivoted at 35 to the frame of the machine. The free end of the lever 34is connected to link 36 by pin 37. The other end of the link isconnected to a crank 38 by a pin 39. Crank 38 is mounted on the shaft 26which carries the sprocket wheel 24.

The shaft 26 also carries a ratchet 41 engaged by a pawl 42 connected tothe crank 38 by pin 43, whereby reciprocation of the link 36, at eachrevolution of the shaft 17, turns the shaft 26 sufticiently to move,through the chain of mechanism described, the lamp-supporting members 12from one station to the next. A pawl 44, pivoted to the table andspring-biased toward the ratchet 41, is provided to hold said ratchet ina station position, while the crank 38 is being returned preparatory tomaking the next indexing movement.

In order to allow for properly-supported travel of the members 21, eachcarries adjacent its upper end a horizontally pivoted roller 45traveling on a track 46 carried by the frame of the machine. The lowerportion of each support member 21 also carries a vertically pivotedroller 47 engaging a track portion 48 supported on the frame of themachine. Each support member has an outstanding rod 49 provided with anormally vertical aperture S1 in which is received an inverted funnelmember 52, secured in place by a set screw 53. In the stem of eachfunnel member is mounted one of the tubular bulb support members 12,held in adjusted position by set screw 54.

Loading, paint spraying and puin! surplus removal The bulbs are loadedon, and with the lower open ends receiving, the support members 12 atboth ends of the machine at the positions in Fig. l marked load Theconveyor is caused to rotate in a counterclockwise direction, carryingthe bulbs one by one to the stationary position marked flush coating,one of said positions being at each side of the machine adjacentopposite ends. The operations at one side only will be described, asthose at the other side are duplicational. The Hush coating operation isillustrated most clearly in Figures 2 and 3, paint being sprayed from anozzle 55, to which it is introduced through pipe 56 from a pump orother suitable device for drawing it from a reservoir (not shown), saidpaint or enamel flowing down over the stationary bulb 11, at the onelocation only for each bulb, and over the flaring lower portion of theinverted funnel member 52, the surplus being caught in a receivingfunnel 57 and returned to said reservoir for recirculation.

After passing to the subsequent positions designated water washing" inFigure l, the lower end of each inverted funnel member is engaged by oneof the rubber ball members 58 on the upper ends of pipes 61 from a washfluid or water supply mechanism 59. Water is fed thereto through exiblehose 62 from a water main or other water supply device (not shown), fromwhence it passes up through manifold 60, the several flexible hoseconnections 70, the funnel stems, sprays out of apertures 63 in thesupporting members 12, from there out of the lower ends of the supportedbulbs 11, carrying with it surplus paint from the lower edges of thebulbs, and is caught in the receiving tank portion 64, from which it iswasted through pipe 65. The device 64 is carried on a lever 66v which ispivoted to the frame of the machine and moved up and down automaticallyby cam 40 acting on roller 50 pivotally carried thereby, to and from thewashing position illustrated in Figure 4. After such washing operationis completed, the device 64 is withdrawn or lowered, a distance shown bythe arrow 50', to the dotted-line position, to allow the supported bulbsto pass on to the next positions.

At the positions designated air blow, mechanism similar to thatillustrated in Figure 4 is provided but, instead of water, drying gas orair is introduced in a similar manner into the bulbs through apertures63 to remove surplus water or wash uid therefrom preparatory to paintdrying and firing.

Paint drying and baking lehr The paint or enamel previously applied tothe bulbs is dried and fired in a lehr generally designated 67 andillustrated in Figures l and 5. This lehr is supplied with heat from agas and air mixture main 68, said mixture passing through a manifoldinto burner orifices 69, where it burns in the chamber 71. The sidewalls 72 of the lehr are lined with ceramic 73. This chamber, as will beseen from Figure 5, is open in the bottom, providing a slot 74 throughwhich pass the supporting members 12 carrying the lamps 11, travelingfrom the open access end to the open exit end of the lehr. The burnersneed only be near the center of the lehr, the products of combustionpassing toward the ends thereof so that the bulbs are gradually heated,dried, and finally baked as they reach the central and hottest parts ofthe lehr, thereafter gradually cooling toward the exit end thereof.Electric strip heaters (not shown) may supplement the products ofcombustion in the preheating section of the lehr.

Cooling and unloading After passing from the exit end of the lehr 67, asviewed in Figures 6, 7 and 8, the bulbs are partially removed from thetubular support members 12 by the lower edges thereof successivelyengaging a series of shelves 74, 75, etc., supported from the frame ofmachine by brackets 76, '77, 78, etc., said shelves 74 and 75alternating from one side to the other, as viewed in Figure 7, so thatthe lower edges of the bulbs are first engaged at one side and rotatedin one direction as they pass therealong, and then engaged at the otherside and rotated in the opposite direction, thereby effecting aneilicient but gradual cooling of the lamps while out of supportingcontact with the hollow support members 12, thus avoiding the likelihoodof cracking due to uneven cooling.

After cooling in this manner in relatively still air, they nally pass topositions near the end of the conveyor where forced cooling is effected,as by means of a fan 79. After this cooling to a moderate temperature,they are unloaded by hand.

From the foregoing it will be seen that we have provided a machine andmethod whereby bulbs are loaded at one end of the machine on hollowvertical supports, the lower ends of which are, and removed at the otherend, after being flush-coated with paint or enamel, with excess removedfrom the bottom edges thereof, by fluidcarrying means which resilientlyregisters inside of said iiared lower portions, excess wash fluidremoved, by similar gas carrying means, and thereafter dried, fired, andcooled in a gradual but expeditious manner, the cooling first beingeffected in still air while the bulbs are rotated, and then quicklycooled as by means of a fan prior to removal.

Although a preferred embodiment of our invention has been disclosed, itwill be understood that modifications are contemplated.

We claim:

l. A machine for automatically coating bulbs comprising a conveyor,means for driving said conveyor and causing it to index from station tostation, means on said conveyor for holding a series of bulbs with theiraxes vertical, means disposed at one station along said conveyor forspraying enamel on the exterior surfaces of said bulbs, one by one, asthey are stationary and indexed thereat, and means at succeedingstations for drying and baking the enamel on said bulbs.

2. A machine for automatically coating bulbs comprising a conveyor,means for driving said conveyor and causing it to index from station tostation, hollow means on said conveyor for holding a series of bulbswith their axes vertical, means disposed at one station along saidconveyor for spraying enamel on the exterior surfaces of said bulbs, oneby one, as they index thereat, means at a succeeding station forintroducing washing fluid through said hollow means for removing surplusenamel from the bottom edge portions of said bulbs, one by one, as theyindex thereat, and means at succeeding stations for drying and bakingthe enamel on said bulbs.

3. A machine for automatically coating bulbs with paint comprising .aconveyor, means for driving said conveyor and causing it to index fromstation to station, hollow means on said conveyor for holding a seriesof bulbs with their axes vertical, means disposed at one station alongsaid conveyor for spraying paint on the exterior surfaces of said bulbs,one by one, as they index thereat, means at a succeeding station forintroducing washing fluid through said hollow holding means, forremoving said surplus paint from the bottom edge portions of said bulbs,one by one, as they index thereat, means at a succeeding station forintroducing drying gas through said hollow holding means for removingadhering washing fluid, and means at succeeding stations for drying andbaking the paint on said bulbs.

4. A machine for automatically coating bulbs with paint comprising aconveyor, means for driving said conveyor and causing it to index fromstation to station, hollow means on said conveyor for holding a seriesof bulbs with their axes vertical, means disposed at one static: alongsaid conveyor for spraying paint on the exterior surfaces of said bulbs,one by one, as they index thereat, means at succeeding stations fordrying and baking said paint on said bulbs, and means for lifting saidbulbs off said hollow supporting means and rotating them while cooling.

5. A machine for automatically coating bulbs with paint comprising aconveyor, means for driving said conveyor and causing it to index fromstation to station, hollow means on said conveyor for holding a seriesof bulbs with their axes vertical, means disposed at one station alongsaid conveyor for spraying paint on the exterior surfaces of said bulbs,one by one, as they index thereat, means at succeeding stations fordrying and baking said paint on said bulbs, means for after bakinglifting said bulbs off said hollow supporting means and rotating themwhile cooling, and means at the final stations for blowing air on saidbulbs to shonten the necessary cooling time prior to removal from themachine.

6. A machine for automatically coating bulbs with paint, comprising aconveyor, means for driving said conveyor and causing it to index fromstation to station, hollow means with flared lower portions on saidconveyor for holding a series of bulbs with their axes vertical, meansdisposed at one station along said conveyor for spraying paint on theexterior surfaces of said bulbs one by one as they index thereat, meansat a succeeding station for resiliently registering inside of said aredlower portions for introducing washing fluid through said hollow holdingmeans for removing surplus paint from the bottom edge portions of saidbulbs, one by one, as they index thereat, means at a succeeding stationfor resiliently registering inside of said flared lower portions forintroducing drying gas through said hollow holding means for removingadhering washing fluid, means at succeeding stations for drying andbaking the paint on said bulbs, shelf means alternating at oppositesides for lifting said bulbs olf said hollow supporting means androtating them in one direction and then in the other while cooling, andfan means at the final stations for blowing air on said lamps to shortenthe necessary cooling time prior to removal from the machine.

7. The method of automatically coating bulbs with paint comprisinginserting a series of said bulbs over a line of stationary hollowholding means, spraying paint on the exterior surface of said bulbs oneby one while stationary, introducing water through said hollow holdingmeans to wash of surplus paint adherent to the bottom edges thereof,blowing air through the same holding means to remove surplus water,drying and baking said bulbs while so held, rotating said bulbs Whilecooling after raising them from said hollow holding means, and nallyblowing air thereon to effect quick cooling thereof.

8. The method of coating open-ended bulbs comprising holding the samestationary with their open ends at the bottom, spraying liquid coatingmaterial thereover from above while so held, and thereafter spraying theinterior of said bulbs with Washing liquid to remove the surplus coatingmaterial from the lower edges of the open end portions thereof.

9. A machine for coating bulbs comprising a conveyor, means for drivingsaid conveyor and causing it to move step by step from one station tothe next, hollow tubular means on said conveyor over which the open endsof bulbs are placed so that the tops of said bulbs are supportedthereby, means disposed at one station along said conveyor for sprayingcoating material on the exterior surfaces of said bulbs, one by onewhile they are held stationary, and means at a succeeding station forintroducing Washing fluid through said tubular means for removingsurplus coating material from the bottom edge portions of said bulbs,one by one, at said succeeding station.

10. A machine for coating bulbs comprising a conveyor, means for drivingsaid conveyor and causing it to move step by step from one station tothe next, hollow tubular means on said conveyor over which the open endsof bulbs are placed so that the tops of said bulbs are supportedthereby, and means disposed at one station along said conveyor forspraying coating material on the exterior surfaces of said bulbs, one byone while they are held stationary.

References Cited in the le of this patent UNITED STATES PATENTS1,589,956 Hageman et al June 22, 1926 1,655,290 Phelps et al Jan. 3,1928 2,141,630 Westin Dec. 27, 1938 2,229,631 Barker et al. Jan. 28,1941 2,270,132 Malloy et al. Jan. 13, 1942 2,342,307 Smith Feb. 22, 19442,420,620 Remington et al. May 13, 1947 2,426,391 Emerson Aug. 26, 1947

1. A MACHINE FOR AUTOMATICALLY COATING BULBS COMPRISING A CONVEYOR,MEANS FOR DRIVING SAID CONVEYOR AND CAUSING IT TO INDEX FROM STATION TOSTATION, MEANS ON SAID CONVEYOR FOR HOLDING A SERIES OF BULBS WITH THEIRAXES VERTICAL, MEANS DISPOSED AT ONE STATION ALONG SAID CONVEYOR FORSPRAYING ENAMEL ON THE EXTERIOR SURFACES OF SAID BULBS, ONE BY ONE, ASTHEY ARE STATIONARY AND INDEXED THEREAT, AND MEANS AT SUCCEEDINGSTATIONS FOR DRYING AND BAKING THE ENAMEL ON SAID BULBS.